1. Field of the Invention
The present invention relates to a starter whose pinion gear is pushed towards a ring gear of the engine side by the operation of an electromagnetic switch then engages with the ring gear whereby the engine is turned over.
2. Description of the Related Art
A starter which cranks an engine by engaging a pinion gear with a ring gear is conventionally known, where the ring gear is provided to a crankshaft of the engine and the pinion gear is pushed on an output shaft towards the ring gear by a gearshift driven by an electromagnetic switch.
The starter described in Japanese Patent Application Laid-Open No. 2003-176767 is an electromagnetic-push-in-type starter. In this type starter, a pinion movable body with which a pinion gear and a one-way clutch were united moves on an output shaft. In order to prevent a foreign substance or water from infiltrating into an inside of the starter from between a pinion movable body and inner circumferential surface of a nose part of a housing, the starter has a ring-shaped seal component in the inner circumferential surface of the nose part. An end of the outer diameter of the seal component is fixed to the inner circumferential surface of the nose part and an end of the inner diameter of the seal component slidably contacts to an outer circumferential surface whereby sealability is secured without restricting movement of the pinion movable body.
The pinion movable body is rotated in response to the torque of a motor at high speed at the time of an operation of the starter of the above-mentioned composition. However, since the seal component is fixed to the inner circumferential surface of the housing, the seal component is not rotated. For this reason, the seal component receives friction by rotation of the pinion movable body. Since the end of the outer diameter of the seal component becomes worn, there is concern that seal performance may deteriorate.